I. Field of the Invention
The present invention relates generally to liquid fuel pumps and, more particularly, to such a pump for an automotive vehicle.
II. Description of Related Art
Many automotive vehicles utilize direct injection internal combustion engines due to the efficiency in fuel economy achieved by such engines. In a direct injection engine, the fuel is injected directly into the combustion chambers or cylinders for the engine.
Since the fuel is injected directly into the engine cylinders, the fuel supply must necessarily be provided at a high pressure sufficient to overcome the pressures existing within the interior of the combustion chambers. Typically, a fuel pump supplies fuel from a source of fuel, such as a fuel tank, to a high pressure fuel injection rail. The fuel injection rail is then fluidly connected to the individual fuel injectors that are mounted on the engine block. The opening and closing timing for each fuel injector for the engine is then controlled by an electronic control system for the vehicle.
The previously known fuel pumps for direct injection engines contribute significantly to the overall cost of the fuel system as well as the amount of room consumed by the fuel pump. Typically, the pump body is made of stainless steel which is an expensive material both to obtain and machine. Furthermore, tight engine packaging also often causes a concern for the placement of the pump.
These previously known pumps are also complex in construction and include numerous internal components. The numerous internal components not only increase the overall cost and expense of the pump, but also create more potential failure modes for the pump. This, in turn, creates more expensive quality control measures due to increased safety concerns over the design, quality, and durability of the multiple parts contained within the fuel pump.
The previously known fuel pumps for direct injection engines are also highly susceptible to contamination of the fuel. Such contamination can entangle in the pump's critical components and render the pump inoperable or otherwise compromised.
The high susceptibility to contamination of these prior pumps results primarily from the complex passageways formed through the pump housing between the inlet and the outlet. Furthermore, because of the complexity of the fuel flow passageways, there oftentimes is limited fuel flow around these components which makes them difficult to fully clean from the fuel flow.